diff --git a/.vscode/settings.json b/.vscode/settings.json
index 524c0d7a..f3a5a8c5 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -99,6 +99,7 @@
     "mworld",
     "nanos",
     "neovim",
+    "newtype",
     "nextest",
     "Nodesource",
     "notcurses",
diff --git a/tui/src/tui/editor/editor_buffer/buffer_selection_support.rs b/tui/src/tui/editor/editor_buffer/buffer_selection_support.rs
index b784339b..ee9d81f7 100644
--- a/tui/src/tui/editor/editor_buffer/buffer_selection_support.rs
+++ b/tui/src/tui/editor/editor_buffer/buffer_selection_support.rs
@@ -55,7 +55,7 @@ pub fn handle_selection_single_line_caret_movement(
 
             let buffer_mut = buffer.get_mut(width(0) + height(0));
 
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 row_index,
                 new_range,
                 SelectionRange::caret_movement_direction_left_right(previous, current),
@@ -120,7 +120,7 @@ pub fn handle_selection_single_line_caret_movement(
             let new_range = range.shrink_end_by(width(*delta));
 
             let buffer_mut = buffer.get_mut(width(0) + height(0));
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 row_index,
                 new_range,
                 SelectionRange::caret_movement_direction_left_right(previous, current),
@@ -137,7 +137,7 @@ pub fn handle_selection_single_line_caret_movement(
             let new_range = range.grow_start_by(width(*delta));
 
             let buffer_mut = buffer.get_mut(width(0) + height(0));
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 row_index,
                 new_range,
                 SelectionRange::caret_movement_direction_left_right(previous, current),
@@ -154,7 +154,7 @@ pub fn handle_selection_single_line_caret_movement(
             let new_range = range.grow_end_by(width(*delta));
 
             let buffer_mut = buffer.get_mut(width(0) + height(0));
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 row_index,
                 new_range,
                 SelectionRange::caret_movement_direction_left_right(previous, current),
@@ -172,7 +172,7 @@ pub fn handle_selection_single_line_caret_movement(
             let new_range = range.shrink_start_by(width(*delta));
 
             let buffer_mut = buffer.get_mut(width(0) + height(0));
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 row_index,
                 new_range,
                 SelectionRange::caret_movement_direction_left_right(previous, current),
@@ -189,7 +189,7 @@ pub fn handle_selection_single_line_caret_movement(
     if let Some(range) = buffer.get_selection_list().get(row_index) {
         if range.start_disp_col_idx_scr_adj == range.end_disp_col_idx_scr_adj {
             let buffer_mut = buffer.get_mut(width(0) + height(0));
-            buffer_mut.sel_list.remove(
+            buffer_mut.inner.sel_list.remove(
                 row_index,
                 SelectionRange::caret_movement_direction_left_right(previous, current),
             );
@@ -301,7 +301,7 @@ pub fn handle_selection_multiline_caret_movement_hit_top_or_bottom_of_document(
             /* 3: row_index */
             d = format!("row_index: {:?}", row_index).green().on_dark_grey(),
             /* 4: selection_map */
-            e = format!("{:?}", buffer_mut.sel_list)
+            e = format!("{:?}", buffer_mut.inner.sel_list)
                 .magenta()
                 .on_dark_grey(),
         );
@@ -314,12 +314,12 @@ pub fn handle_selection_multiline_caret_movement_hit_top_or_bottom_of_document(
 
     match curr.col_index.cmp(&prev.col_index) {
         cmp::Ordering::Less => {
-            match buffer_mut.sel_list.get(row_index) {
+            match buffer_mut.inner.sel_list.get(row_index) {
                 // Extend range to left (caret moved up and hit the top).
                 Some(range) => {
                     let start = col(0);
                     let end = range.end_disp_col_idx_scr_adj;
-                    buffer_mut.sel_list.insert(
+                    buffer_mut.inner.sel_list.insert(
                         row_index,
                         SelectionRange {
                             start_disp_col_idx_scr_adj: start,
@@ -332,7 +332,7 @@ pub fn handle_selection_multiline_caret_movement_hit_top_or_bottom_of_document(
                 None => {
                     let start = col(0);
                     let end = prev.col_index;
-                    buffer_mut.sel_list.insert(
+                    buffer_mut.inner.sel_list.insert(
                         row_index,
                         SelectionRange {
                             start_disp_col_idx_scr_adj: start,
@@ -344,17 +344,17 @@ pub fn handle_selection_multiline_caret_movement_hit_top_or_bottom_of_document(
             }
         }
         cmp::Ordering::Greater => {
-            match buffer_mut.sel_list.get(row_index) {
+            match buffer_mut.inner.sel_list.get(row_index) {
                 // Extend range to right (caret moved down and hit bottom).
                 Some(range) => {
-                    if let Some(line_us) = buffer_mut.lines.get(usize(row_index)) {
+                    if let Some(line_us) = buffer_mut.inner.lines.get(usize(row_index)) {
                         let start = range.start_disp_col_idx_scr_adj;
                         // For selection, go one col index past the end of the line,
                         // since selection range is not inclusive of the end index.
                         let end = caret_scroll_index::col_index_for_width(
                             line_us.display_width,
                         );
-                        buffer_mut.sel_list.insert(
+                        buffer_mut.inner.sel_list.insert(
                             row_index,
                             SelectionRange {
                                 start_disp_col_idx_scr_adj: start,
@@ -368,7 +368,7 @@ pub fn handle_selection_multiline_caret_movement_hit_top_or_bottom_of_document(
                 None => {
                     let start = prev.col_index;
                     let end = curr.col_index;
-                    buffer_mut.sel_list.insert(
+                    buffer_mut.inner.sel_list.insert(
                         row_index,
                         SelectionRange {
                             start_disp_col_idx_scr_adj: start,
@@ -650,12 +650,12 @@ mod multiline_select_helpers {
         };
 
         let buffer_mut = buffer.get_mut(width(0) + height(0));
-        buffer_mut.sel_list.insert(
+        buffer_mut.inner.sel_list.insert(
             first.row_index,
             first_row_range,
             caret_vertical_movement_direction,
         );
-        buffer_mut.sel_list.insert(
+        buffer_mut.inner.sel_list.insert(
             last.row_index,
             last_row_range,
             caret_vertical_movement_direction,
@@ -681,7 +681,7 @@ mod multiline_select_helpers {
         let buffer_mut = buffer.get_mut(width(0) + height(0));
 
         // Extend the existing range (in selection map) for the first row to end of line.
-        if let Some(first_row_range) = buffer_mut.sel_list.get(first.row_index) {
+        if let Some(first_row_range) = buffer_mut.inner.sel_list.get(first.row_index) {
             let start_col = first_row_range.start_disp_col_idx_scr_adj;
             // Go one col index past the end of the width, since selection range is not
             // inclusive of end index.
@@ -690,7 +690,7 @@ mod multiline_select_helpers {
                 start_disp_col_idx_scr_adj: start_col,
                 end_disp_col_idx_scr_adj: end_col,
             };
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 first.row_index,
                 new_first_row_range,
                 caret_vertical_movement_direction,
@@ -703,7 +703,7 @@ mod multiline_select_helpers {
             let end_col = last.col_index;
             (start_col, end_col).into()
         };
-        buffer_mut.sel_list.insert(
+        buffer_mut.inner.sel_list.insert(
             last.row_index,
             last_row_range,
             caret_vertical_movement_direction,
@@ -729,7 +729,7 @@ mod multiline_select_helpers {
         let buffer_mut = buffer.get_mut(width(0) + height(0));
 
         // FIRST ROW.
-        if let Some(first_row_range) = buffer_mut.sel_list.get(first.row_index) {
+        if let Some(first_row_range) = buffer_mut.inner.sel_list.get(first.row_index) {
             // Extend the existing range (in selection map) for the first row to end of line.
             let updated_first_row_range = SelectionRange {
                 start_disp_col_idx_scr_adj: first_row_range.start_disp_col_idx_scr_adj,
@@ -738,7 +738,7 @@ mod multiline_select_helpers {
                 // not inclusive of end index.
                 caret_scroll_index::col_index_for_width(first_line_width),
             };
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 first.row_index,
                 updated_first_row_range,
                 caret_vertical_movement_direction,
@@ -756,7 +756,7 @@ mod multiline_select_helpers {
                 )
                     .into()
             };
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 first.row_index,
                 new_first_row_range,
                 caret_vertical_movement_direction,
@@ -764,7 +764,7 @@ mod multiline_select_helpers {
         }
 
         // LAST ROW.
-        if let Some(last_row_range) = buffer_mut.sel_list.get(last.row_index) {
+        if let Some(last_row_range) = buffer_mut.inner.sel_list.get(last.row_index) {
             // Extend the existing range (in selection map) for the last row to start of line.
             let start_col = col(0);
             let end_col = last_row_range.end_disp_col_idx_scr_adj;
@@ -772,7 +772,7 @@ mod multiline_select_helpers {
                 start_disp_col_idx_scr_adj: start_col,
                 end_disp_col_idx_scr_adj: end_col,
             };
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 last.row_index,
                 updated_last_row_range,
                 caret_vertical_movement_direction,
@@ -784,7 +784,7 @@ mod multiline_select_helpers {
                 let end_col = last.col_index;
                 (start_col, end_col).into()
             };
-            buffer_mut.sel_list.insert(
+            buffer_mut.inner.sel_list.insert(
                 last.row_index,
                 new_last_row_range,
                 caret_vertical_movement_direction,
@@ -808,24 +808,26 @@ mod multiline_select_helpers {
         let buffer_mut = buffer.get_mut(width(0) + height(0));
 
         // Drop the existing range (in selection map) for the last row.
-        if buffer_mut.sel_list.get(last.row_index).is_some() {
+        if buffer_mut.inner.sel_list.get(last.row_index).is_some() {
             buffer_mut
+                .inner
                 .sel_list
                 .remove(last.row_index, caret_vertical_movement_direction);
         }
 
         // Change the existing range (in selection map) for the first row.
-        if let Some(first_row_range) = buffer_mut.sel_list.get(first.row_index) {
+        if let Some(first_row_range) = buffer_mut.inner.sel_list.get(first.row_index) {
             let lhs = first_row_range.start_disp_col_idx_scr_adj;
             let rhs = first.col_index;
             match lhs.cmp(&rhs) {
                 cmp::Ordering::Equal => {
                     buffer_mut
+                        .inner
                         .sel_list
                         .remove(first.row_index, caret_vertical_movement_direction);
                 }
                 cmp::Ordering::Less | cmp::Ordering::Greater => {
-                    buffer_mut.sel_list.insert(
+                    buffer_mut.inner.sel_list.insert(
                         first.row_index,
                         SelectionRange {
                             start_disp_col_idx_scr_adj: lhs.min(rhs),
@@ -854,23 +856,25 @@ mod multiline_select_helpers {
         let buffer_mut = buffer.get_mut(width(0) + height(0));
 
         // Drop the existing range (in selection map) for the first row.
-        if buffer_mut.sel_list.get(first.row_index).is_some() {
+        if buffer_mut.inner.sel_list.get(first.row_index).is_some() {
             buffer_mut
+                .inner
                 .sel_list
                 .remove(first.row_index, caret_vertical_movement_direction);
         }
 
         // Change the existing range (in selection map) for the last row.
-        if let Some(last_row_range) = buffer_mut.sel_list.get(last.row_index) {
+        if let Some(last_row_range) = buffer_mut.inner.sel_list.get(last.row_index) {
             let lhs = last.col_index;
             let rhs = last_row_range.end_disp_col_idx_scr_adj;
             let row_index = last.row_index;
             match lhs.cmp(&rhs) {
                 cmp::Ordering::Equal => buffer_mut
+                    .inner
                     .sel_list
                     .remove(row_index, caret_vertical_movement_direction),
                 cmp::Ordering::Greater | cmp::Ordering::Less => {
-                    buffer_mut.sel_list.insert(
+                    buffer_mut.inner.sel_list.insert(
                         row_index,
                         SelectionRange {
                             start_disp_col_idx_scr_adj: rhs.min(lhs),
diff --git a/tui/src/tui/editor/editor_buffer/buffer_struct.rs b/tui/src/tui/editor/editor_buffer/buffer_struct.rs
index a3a9c6a2..86405e63 100644
--- a/tui/src/tui/editor/editor_buffer/buffer_struct.rs
+++ b/tui/src/tui/editor/editor_buffer/buffer_struct.rs
@@ -33,6 +33,7 @@ use r3bl_core::{call_if_true,
                 CharStorage,
                 ColWidth,
                 Dim,
+                RowHeight,
                 RowIndex,
                 ScrOfs,
                 Size,
@@ -47,7 +48,7 @@ use smallvec::{smallvec, SmallVec};
 use super::SelectionList;
 use crate::{caret_locate,
             editor_engine::engine_public_api,
-            validate_buffer_mut::EditorBufferMut,
+            validate_buffer_mut::{EditorBufferMutNoDrop, EditorBufferMutWithDrop},
             EditorEngine,
             HasFocus,
             RenderArgs,
@@ -82,9 +83,10 @@ use crate::{caret_locate,
 /// All the fields in this struct are private. In order to access them you have to use the
 /// accessor associated functions. To mutate them, you have to use the
 /// [get_mut](EditorBuffer::get_mut) method, which returns a struct of mutable references
-/// to the fields. This struct [EditorBufferMut] implements the [Drop] trait, which allows
-/// for validation [crate::validate_buffer_mut::perform_validation_checks_after_mutation]
-/// operations to be applied post mutation.
+/// to the fields. This struct [crate::EditorBufferMut] implements the [Drop] trait, which
+/// allows for validation
+/// [crate::validate_buffer_mut::perform_validation_checks_after_mutation] operations to
+/// be applied post mutation.
 ///
 /// # Different kinds of caret positions
 ///
@@ -367,7 +369,7 @@ pub mod content {
         }
 
         /// Get line display with at caret's scroll adjusted row index. Use this when you
-        /// don't have access to this struct. Eg: in [EditorBufferMut].
+        /// don't have access to this struct. Eg: in [crate::EditorBufferMut].
         pub fn impl_get_line_display_width_at_caret_scr_adj(
             caret_raw: CaretRaw,
             scr_ofs: ScrOfs,
@@ -506,8 +508,6 @@ pub mod content {
 }
 
 pub mod access_and_mutate {
-    use r3bl_core::RowHeight;
-
     use super::*;
 
     impl EditorBuffer {
@@ -615,16 +615,16 @@ pub mod access_and_mutate {
         /// This makes it easy to determine what code mutates this struct, since it is
         /// necessary to validate things after mutation quite a bit in editor_ops.rs.
         ///
-        /// [EditorBufferMut] implements the [Drop] trait, which ensures that any
+        /// [crate::EditorBufferMut] implements the [Drop] trait, which ensures that any
         /// validation changes are applied after making changes to the [EditorBuffer].
-        pub fn get_mut(&mut self, vp: Dim) -> EditorBufferMut<'_> {
-            EditorBufferMut {
-                lines: &mut self.content.lines,
-                caret_raw: &mut self.content.caret_raw,
-                scr_ofs: &mut self.content.scr_ofs,
-                sel_list: &mut self.content.sel_list,
+        pub fn get_mut(&mut self, vp: Dim) -> EditorBufferMutWithDrop<'_> {
+            EditorBufferMutWithDrop::new(
+                &mut self.content.lines,
+                &mut self.content.caret_raw,
+                &mut self.content.scr_ofs,
+                &mut self.content.sel_list,
                 vp,
-            }
+            )
         }
 
         /// This is a special case of [EditorBuffer::get_mut] where the [Drop] trait is
@@ -632,13 +632,13 @@ pub mod access_and_mutate {
         /// don't want to run validation checks after mutation, which happens when the
         /// window is resized using [mod@crate::validate_scroll_on_resize].
         pub fn get_mut_no_drop(&mut self, vp: Dim) -> EditorBufferMutNoDrop<'_> {
-            EditorBufferMutNoDrop {
-                lines: &mut self.content.lines,
-                caret_raw: &mut self.content.caret_raw,
-                scr_ofs: &mut self.content.scr_ofs,
-                sel_list: &mut self.content.sel_list,
+            EditorBufferMutNoDrop::new(
+                &mut self.content.lines,
+                &mut self.content.caret_raw,
+                &mut self.content.scr_ofs,
+                &mut self.content.sel_list,
                 vp,
-            }
+            )
         }
 
         pub fn has_selection(&self) -> bool { !self.content.sel_list.is_empty() }
@@ -649,20 +649,6 @@ pub mod access_and_mutate {
     }
 }
 
-pub struct EditorBufferMutNoDrop<'a> {
-    pub lines: &'a mut VecEditorContentLines,
-    pub caret_raw: &'a mut CaretRaw,
-    pub scr_ofs: &'a mut ScrOfs,
-    pub sel_list: &'a mut SelectionList,
-    /// - Viewport width is optional because it's only needed for caret validation.
-    ///   And you can get it from [crate::EditorEngine]. You can pass `0` if you don't have
-    ///   it.
-    /// - Viewport height is optional because it's only needed for caret validation.
-    ///   And you can get it from [crate::EditorEngine]. You can pass `0` if you don't have
-    ///   it.
-    pub vp: Dim,
-}
-
 pub mod history {
     use super::*;
 
diff --git a/tui/src/tui/editor/editor_engine/caret_mut.rs b/tui/src/tui/editor/editor_engine/caret_mut.rs
index acd659a5..897817d2 100644
--- a/tui/src/tui/editor/editor_engine/caret_mut.rs
+++ b/tui/src/tui/editor/editor_engine/caret_mut.rs
@@ -49,8 +49,8 @@ pub fn up(buffer: &mut EditorBuffer, engine: &mut EditorEngine, sel_mod: SelectM
                     let buffer_mut = buffer.get_mut(engine.viewport());
 
                     scroll_editor_content::reset_caret_col(
-                        buffer_mut.caret_raw,
-                        buffer_mut.scr_ofs,
+                        buffer_mut.inner.caret_raw,
+                        buffer_mut.inner.scr_ofs,
                     );
                 }
             }
@@ -64,8 +64,8 @@ pub fn up(buffer: &mut EditorBuffer, engine: &mut EditorEngine, sel_mod: SelectM
                     let buffer_mut = buffer.get_mut(engine.viewport());
 
                     scroll_editor_content::dec_caret_row(
-                        buffer_mut.caret_raw,
-                        buffer_mut.scr_ofs,
+                        buffer_mut.inner.caret_raw,
+                        buffer_mut.inner.scr_ofs,
                     );
                 }
 
@@ -133,9 +133,9 @@ pub fn down(buffer: &mut EditorBuffer, engine: &mut EditorEngine, sel_mod: Selec
             let buffer_mut = buffer.get_mut(engine.viewport());
 
             scroll_editor_content::inc_caret_row(
-                buffer_mut.caret_raw,
-                buffer_mut.scr_ofs,
-                buffer_mut.vp.row_height,
+                buffer_mut.inner.caret_raw,
+                buffer_mut.inner.scr_ofs,
+                buffer_mut.inner.vp.row_height,
             );
         }
 
@@ -213,8 +213,8 @@ pub fn to_start_of_line(
                 let buffer_mut = buffer.get_mut(engine.viewport());
 
                 scroll_editor_content::reset_caret_col(
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
                 );
             }
         }
@@ -255,9 +255,9 @@ pub fn to_end_of_line(
                     // - `line_display_width` which is the same as:
                     // - `line_display_width.convert_to_col_index() /*-1*/ + 1`
                     caret_scroll_index::col_index_for_width(line_display_width),
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
-                    buffer_mut.vp.col_width,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
+                    buffer_mut.inner.vp.col_width,
                     line_display_width,
                 );
             }
@@ -380,11 +380,11 @@ pub fn right(buffer: &mut EditorBuffer, engine: &mut EditorEngine, sel_mod: Sele
                             let buffer_mut = buffer.get_mut(engine.viewport());
 
                             scroll_editor_content::inc_caret_col_by(
-                                buffer_mut.caret_raw,
-                                buffer_mut.scr_ofs,
+                                buffer_mut.inner.caret_raw,
+                                buffer_mut.inner.scr_ofs,
                                 jump_by_col_width,
                                 max_display_width,
-                                buffer_mut.vp.col_width,
+                                buffer_mut.inner.vp.col_width,
                             );
                         }
 
@@ -395,8 +395,8 @@ pub fn right(buffer: &mut EditorBuffer, engine: &mut EditorEngine, sel_mod: Sele
                                 let buffer_mut = buffer.get_mut(engine.viewport());
 
                                 scroll_editor_content::dec_caret_col_by(
-                                    buffer_mut.caret_raw,
-                                    buffer_mut.scr_ofs,
+                                    buffer_mut.inner.caret_raw,
+                                    buffer_mut.inner.scr_ofs,
                                     move_left_by_amt,
                                 );
                             }
@@ -408,11 +408,11 @@ pub fn right(buffer: &mut EditorBuffer, engine: &mut EditorEngine, sel_mod: Sele
                             let buffer_mut = buffer.get_mut(engine.viewport());
 
                             scroll_editor_content::inc_caret_col_by(
-                                buffer_mut.caret_raw,
-                                buffer_mut.scr_ofs,
+                                buffer_mut.inner.caret_raw,
+                                buffer_mut.inner.scr_ofs,
                                 unicode_width_at_caret,
                                 max_display_width,
-                                buffer_mut.vp.col_width,
+                                buffer_mut.inner.vp.col_width,
                             );
                         }
                     }
@@ -425,11 +425,11 @@ pub fn right(buffer: &mut EditorBuffer, engine: &mut EditorEngine, sel_mod: Sele
                         let buffer_mut = buffer.get_mut(engine.viewport());
 
                         scroll_editor_content::inc_caret_col_by(
-                            buffer_mut.caret_raw,
-                            buffer_mut.scr_ofs,
+                            buffer_mut.inner.caret_raw,
+                            buffer_mut.inner.scr_ofs,
                             unicode_width_at_caret,
                             max_display_width,
-                            buffer_mut.vp.col_width,
+                            buffer_mut.inner.vp.col_width,
                         );
                     }
                 }
@@ -449,14 +449,14 @@ pub fn right(buffer: &mut EditorBuffer, engine: &mut EditorEngine, sel_mod: Sele
                     let buffer_mut = buffer.get_mut(engine.viewport());
 
                     scroll_editor_content::inc_caret_row(
-                        buffer_mut.caret_raw,
-                        buffer_mut.scr_ofs,
-                        buffer_mut.vp.row_height,
+                        buffer_mut.inner.caret_raw,
+                        buffer_mut.inner.scr_ofs,
+                        buffer_mut.inner.vp.row_height,
                     );
 
                     scroll_editor_content::reset_caret_col(
-                        buffer_mut.caret_raw,
-                        buffer_mut.scr_ofs,
+                        buffer_mut.inner.caret_raw,
+                        buffer_mut.inner.scr_ofs,
                     );
                 }
             }
@@ -486,8 +486,8 @@ pub fn left(
                     let buffer_mut = buffer.get_mut(editor.viewport());
 
                     scroll_editor_content::dec_caret_row(
-                        buffer_mut.caret_raw,
-                        buffer_mut.scr_ofs,
+                        buffer_mut.inner.caret_raw,
+                        buffer_mut.inner.scr_ofs,
                     );
                 }
 
@@ -502,8 +502,8 @@ pub fn left(
                 let buffer_mut = buffer.get_mut(editor.viewport());
 
                 scroll_editor_content::dec_caret_col_by(
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
                     seg_slice.seg_display_width,
                 );
             }
@@ -516,8 +516,8 @@ pub fn left(
                 let buffer_mut = buffer.get_mut(editor.viewport());
 
                 scroll_editor_content::dec_caret_col_by(
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
                     seg_slice.seg_display_width,
                 );
             }
diff --git a/tui/src/tui/editor/editor_engine/content_mut.rs b/tui/src/tui/editor/editor_engine/content_mut.rs
index 6617608c..f0a41ff2 100644
--- a/tui/src/tui/editor/editor_engine/content_mut.rs
+++ b/tui/src/tui/editor/editor_engine/content_mut.rs
@@ -68,7 +68,7 @@ pub fn insert_new_line_at_caret(args: EditorArgsMut<'_>) {
         // validation performed.
         {
             let buffer_mut = buffer.get_mut(engine.viewport());
-            buffer_mut.lines.push("".unicode_string());
+            buffer_mut.inner.lines.push("".unicode_string());
         }
         return;
     }
@@ -107,17 +107,18 @@ pub fn insert_new_line_at_caret(args: EditorArgsMut<'_>) {
                 let buffer_mut = buffer.get_mut(engine.viewport());
 
                 let new_row_index = scroll_editor_content::inc_caret_row(
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
-                    buffer_mut.vp.row_height,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
+                    buffer_mut.inner.vp.row_height,
                 );
 
                 scroll_editor_content::reset_caret_col(
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
                 );
 
                 buffer_mut
+                    .inner
                     .lines
                     .insert(new_row_index.as_usize(), "".unicode_string());
             }
@@ -132,8 +133,9 @@ pub fn insert_new_line_at_caret(args: EditorArgsMut<'_>) {
             {
                 let buffer_mut = buffer.get_mut(engine.viewport());
                 let cur_row_index =
-                    (*buffer_mut.caret_raw + *buffer_mut.scr_ofs).row_index;
+                    (*buffer_mut.inner.caret_raw + *buffer_mut.inner.scr_ofs).row_index;
                 buffer_mut
+                    .inner
                     .lines
                     .insert(cur_row_index.as_usize(), "".unicode_string());
             }
@@ -143,9 +145,9 @@ pub fn insert_new_line_at_caret(args: EditorArgsMut<'_>) {
             {
                 let buffer_mut = buffer.get_mut(engine.viewport());
                 scroll_editor_content::inc_caret_row(
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
-                    buffer_mut.vp.row_height,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
+                    buffer_mut.inner.vp.row_height,
                 );
             }
         }
@@ -167,23 +169,24 @@ pub fn insert_new_line_at_caret(args: EditorArgsMut<'_>) {
                         let buffer_mut = buffer.get_mut(engine.viewport());
 
                         let _ = std::mem::replace(
-                            &mut buffer_mut.lines[row_index],
+                            &mut buffer_mut.inner.lines[row_index],
                             left_string.unicode_string(),
                         );
 
                         buffer_mut
+                            .inner
                             .lines
                             .insert(row_index + 1, right_string.unicode_string());
 
                         scroll_editor_content::inc_caret_row(
-                            buffer_mut.caret_raw,
-                            buffer_mut.scr_ofs,
-                            buffer_mut.vp.row_height,
+                            buffer_mut.inner.caret_raw,
+                            buffer_mut.inner.scr_ofs,
+                            buffer_mut.inner.vp.row_height,
                         );
 
                         scroll_editor_content::reset_caret_col(
-                            buffer_mut.caret_raw,
-                            buffer_mut.scr_ofs,
+                            buffer_mut.inner.caret_raw,
+                            buffer_mut.inner.scr_ofs,
                         );
                     }
                 }
@@ -230,9 +233,10 @@ pub fn delete_at_caret(
             // validation performed.
             {
                 let buffer_mut = buffer.get_mut(engine.viewport());
-                let row_index = (*buffer_mut.caret_raw + *buffer_mut.scr_ofs).row_index;
+                let row_index =
+                    (*buffer_mut.inner.caret_raw + *buffer_mut.inner.scr_ofs).row_index;
                 let _ = std::mem::replace(
-                    &mut buffer_mut.lines[row_index.as_usize()],
+                    &mut buffer_mut.inner.lines[row_index.as_usize()],
                     new_line_content.unicode_string(),
                 );
             }
@@ -261,12 +265,13 @@ pub fn delete_at_caret(
             // validation performed.
             {
                 let buffer_mut = buffer.get_mut(engine.viewport());
-                let row_index = (*buffer_mut.caret_raw + *buffer_mut.scr_ofs).row_index;
+                let row_index =
+                    (*buffer_mut.inner.caret_raw + *buffer_mut.inner.scr_ofs).row_index;
                 let _ = std::mem::replace(
-                    &mut buffer_mut.lines[row_index.as_usize()],
+                    &mut buffer_mut.inner.lines[row_index.as_usize()],
                     new_line_content.unicode_string(),
                 );
-                buffer_mut.lines.remove(row_index.as_usize() + 1);
+                buffer_mut.inner.lines.remove(row_index.as_usize() + 1);
             }
 
             None
@@ -320,20 +325,20 @@ pub fn backspace_at_caret(
             {
                 let buffer_mut = buffer.get_mut(engine.viewport());
                 let cur_row_index =
-                    (*buffer_mut.caret_raw + *buffer_mut.scr_ofs).row_index;
+                    (*buffer_mut.inner.caret_raw + *buffer_mut.inner.scr_ofs).row_index;
                 let _ = std::mem::replace(
-                    &mut buffer_mut.lines[cur_row_index.as_usize()],
+                    &mut buffer_mut.inner.lines[cur_row_index.as_usize()],
                     new_line_content.unicode_string(),
                 );
 
                 let new_line_content_display_width =
-                    buffer_mut.lines[cur_row_index.as_usize()].display_width;
+                    buffer_mut.inner.lines[cur_row_index.as_usize()].display_width;
 
                 scroll_editor_content::set_caret_col_to(
                     delete_at_this_display_col,
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
-                    buffer_mut.vp.col_width,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
+                    buffer_mut.inner.vp.col_width,
                     new_line_content_display_width,
                 );
             }
@@ -371,24 +376,25 @@ pub fn backspace_at_caret(
                 let buffer_mut = buffer.get_mut(engine.viewport());
 
                 let prev_row_index =
-                    (*buffer_mut.caret_raw + *buffer_mut.scr_ofs).row_index - row(1);
+                    (*buffer_mut.inner.caret_raw + *buffer_mut.inner.scr_ofs).row_index
+                        - row(1);
 
                 let cur_row_index =
-                    (*buffer_mut.caret_raw + *buffer_mut.scr_ofs).row_index;
+                    (*buffer_mut.inner.caret_raw + *buffer_mut.inner.scr_ofs).row_index;
 
                 let _ = std::mem::replace(
-                    &mut buffer_mut.lines[prev_row_index.as_usize()],
+                    &mut buffer_mut.inner.lines[prev_row_index.as_usize()],
                     new_line_content.unicode_string(),
                 );
 
                 let new_line_content_display_width =
-                    buffer_mut.lines[prev_row_index.as_usize()].display_width;
+                    buffer_mut.inner.lines[prev_row_index.as_usize()].display_width;
 
-                buffer_mut.lines.remove(cur_row_index.as_usize());
+                buffer_mut.inner.lines.remove(cur_row_index.as_usize());
 
                 scroll_editor_content::dec_caret_row(
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
                 );
 
                 scroll_editor_content::set_caret_col_to(
@@ -396,9 +402,9 @@ pub fn backspace_at_caret(
                     // - `prev_line_display_width` which is the same as:
                     // - `prev_line_display_width.convert_to_col_index() /*-1*/ + 1`
                     caret_scroll_index::col_index_for_width(prev_line_display_width),
-                    buffer_mut.caret_raw,
-                    buffer_mut.scr_ofs,
-                    buffer_mut.vp.col_width,
+                    buffer_mut.inner.caret_raw,
+                    buffer_mut.inner.scr_ofs,
+                    buffer_mut.inner.vp.col_width,
                     new_line_content_display_width,
                 );
             }
@@ -476,7 +482,7 @@ pub fn delete_selected(
         for row_index in map_lines_to_replace.keys() {
             let new_line_content = map_lines_to_replace[row_index].clone();
             let _ = std::mem::replace(
-                &mut buffer_mut.lines[row_index.as_usize()],
+                &mut buffer_mut.inner.lines[row_index.as_usize()],
                 new_line_content.unicode_string(),
             );
         }
@@ -484,7 +490,7 @@ pub fn delete_selected(
         // Remove lines in inverse order, in order to preserve the validity of indices.
         vec_row_indices_to_remove.reverse();
         for row_index in vec_row_indices_to_remove {
-            buffer_mut.lines.remove(row_index.as_usize());
+            buffer_mut.inner.lines.remove(row_index.as_usize());
         }
 
         // Restore caret position to start of selection range.
@@ -493,9 +499,9 @@ pub fn delete_selected(
 
         if let Some(new_caret_scr_adj) = maybe_new_caret {
             // Convert scroll adjusted caret to raw caret by applying scroll offset.
-            // Equivalent to: `let caret_raw = *new_caret_scr_adj - *buffer_mut.scr_ofs;`
-            let caret_raw = new_caret_scr_adj + *buffer_mut.scr_ofs;
-            *buffer_mut.caret_raw = caret_raw;
+            // Equivalent to: `let caret_raw = *new_caret_scr_adj - *buffer_mut.inner.scr_ofs;`
+            let caret_raw = new_caret_scr_adj + *buffer_mut.inner.scr_ofs;
+            *buffer_mut.inner.caret_raw = caret_raw;
         }
     }
 
@@ -523,20 +529,20 @@ fn insert_into_existing_line(
 
         // Replace existing line w/ new line.
         let _ = std::mem::replace(
-            &mut buffer_mut.lines[row_index.as_usize()],
+            &mut buffer_mut.inner.lines[row_index.as_usize()],
             new_line_content.unicode_string(),
         );
 
         let new_line_content_display_width =
-            buffer_mut.lines[row_index.as_usize()].display_width;
+            buffer_mut.inner.lines[row_index.as_usize()].display_width;
 
         // Update caret position.
         scroll_editor_content::inc_caret_col_by(
-            buffer_mut.caret_raw,
-            buffer_mut.scr_ofs,
+            buffer_mut.inner.caret_raw,
+            buffer_mut.inner.scr_ofs,
             chunk_display_width,
             new_line_content_display_width,
-            buffer_mut.vp.col_width,
+            buffer_mut.inner.vp.col_width,
         );
     }
 
@@ -557,7 +563,7 @@ fn fill_in_missing_lines_up_to_row(args: EditorArgsMut<'_>, row_index: RowIndex)
                 // performed.
                 {
                     let buffer_mut = buffer.get_mut(engine.viewport());
-                    buffer_mut.lines.push("".unicode_string());
+                    buffer_mut.inner.lines.push("".unicode_string());
                 }
             }
         }
@@ -581,19 +587,22 @@ fn insert_chunk_into_new_line(
 
         // Actually add the character to the correct line.
         let new_content = chunk.unicode_string();
-        let _ = std::mem::replace(&mut buffer_mut.lines[row_index_scr_adj], new_content);
+        let _ = std::mem::replace(
+            &mut buffer_mut.inner.lines[row_index_scr_adj],
+            new_content,
+        );
 
-        let line_content = &buffer_mut.lines[row_index_scr_adj];
+        let line_content = &buffer_mut.inner.lines[row_index_scr_adj];
         let line_content_display_width = line_content.display_width;
         let col_amt = UnicodeString::str_display_width(chunk);
 
         // Update caret position.
         scroll_editor_content::inc_caret_col_by(
-            buffer_mut.caret_raw,
-            buffer_mut.scr_ofs,
+            buffer_mut.inner.caret_raw,
+            buffer_mut.inner.scr_ofs,
             col_amt,
             line_content_display_width,
-            buffer_mut.vp.col_width,
+            buffer_mut.inner.vp.col_width,
         );
     }
 
diff --git a/tui/src/tui/editor/editor_engine/mod.rs b/tui/src/tui/editor/editor_engine/mod.rs
index 0ee52ed5..b0dfa821 100644
--- a/tui/src/tui/editor/editor_engine/mod.rs
+++ b/tui/src/tui/editor/editor_engine/mod.rs
@@ -31,4 +31,5 @@ pub mod validate_scroll_on_resize;
 pub use engine_public_api::*;
 pub use engine_struct::*;
 pub use select_mode::*;
+pub use validate_buffer_mut::*;
 pub use validate_scroll_on_resize::*;
diff --git a/tui/src/tui/editor/editor_engine/scroll_editor_content.rs b/tui/src/tui/editor/editor_engine/scroll_editor_content.rs
index 5a2e0aa8..0a90b304 100644
--- a/tui/src/tui/editor/editor_engine/scroll_editor_content.rs
+++ b/tui/src/tui/editor/editor_engine/scroll_editor_content.rs
@@ -372,9 +372,9 @@ pub fn change_caret_row_by(
 
                 while diff > row(0) {
                     inc_caret_row(
-                        buffer_mut.caret_raw,
-                        buffer_mut.scr_ofs,
-                        buffer_mut.vp.row_height,
+                        buffer_mut.inner.caret_raw,
+                        buffer_mut.inner.scr_ofs,
+                        buffer_mut.inner.vp.row_height,
                     );
                     diff -= row(1);
                 }
@@ -389,11 +389,11 @@ pub fn change_caret_row_by(
                 let buffer_mut = buffer.get_mut(engine.viewport());
 
                 while diff > height(0) {
-                    dec_caret_row(buffer_mut.caret_raw, buffer_mut.scr_ofs);
+                    dec_caret_row(buffer_mut.inner.caret_raw, buffer_mut.inner.scr_ofs);
                     diff -= height(1);
                     let row_index = {
-                        let lhs = *buffer_mut.caret_raw;
-                        let rhs = *buffer_mut.scr_ofs;
+                        let lhs = *buffer_mut.inner.caret_raw;
+                        let rhs = *buffer_mut.inner.scr_ofs;
                         let it = lhs + rhs;
                         it.row_index
                     };
diff --git a/tui/src/tui/editor/editor_engine/validate_buffer_mut.rs b/tui/src/tui/editor/editor_engine/validate_buffer_mut.rs
index 07af6215..097f7fbe 100644
--- a/tui/src/tui/editor/editor_engine/validate_buffer_mut.rs
+++ b/tui/src/tui/editor/editor_engine/validate_buffer_mut.rs
@@ -15,47 +15,136 @@
  *   limitations under the License.
  */
 
+//! [EditorBufferMut] holds a few important mutable references to the editor buffer. It
+//! also contains some data copied from the editor engine. This is necessary when you need
+//! to mutate the buffer and then run validation checks on the buffer.
+//!
+//! The ["newtype"
+//! pattern](https://doc.rust-lang.org/rust-by-example/generics/new_types.html) is used
+//! here to wrap the underlying [EditorBufferMut] struct, so that it be used in one of two
+//! distinct use cases:
+//! 1. Once [EditorBuffer::get_mut()] is called, the buffer is mutated and then the
+//!    validation checks are run. This is done by using [EditorBufferMutWithDrop].
+//! 2. If you don't want the buffer to be mutated, then you can use
+//!    [EditorBufferMutNoDrop] by calling [EditorBuffer::get_mut_no_drop()].
+
 use r3bl_core::{col, usize, width, CaretRaw, ColWidth, Dim, ScrOfs};
 
 use super::scroll_editor_content;
 use crate::{editor::sizing::VecEditorContentLines, EditorBuffer, SelectionList};
 
-/// See the [Drop] implementation of `EditorBufferMut` which runs
-/// [crate::validate_buffer_mut::perform_validation_checks_after_mutation].
-///
-/// Due to the nature of `UTF-8` and its variable width characters, where the memory size
-/// is not the same as display size. Eg: `a` is 1 byte and 1 display width (unicode
-/// segment width display). `😄` is 3 bytes but it's display width is 2! To ensure that
-/// caret position and scroll offset positions are not in the middle of a unicode segment
-/// character, we need to run the validation checks.
 pub struct EditorBufferMut<'a> {
     pub lines: &'a mut VecEditorContentLines,
     pub caret_raw: &'a mut CaretRaw,
     pub scr_ofs: &'a mut ScrOfs,
     pub sel_list: &'a mut SelectionList,
     /// - Viewport width is optional because it's only needed for caret validation.
-    ///   And you can get it from [super::EditorEngine]. You can pass `0` if you don't have
+    ///   And you can get it from [crate::EditorEngine]. You can pass `0` if you don't have
     ///   it.
     /// - Viewport height is optional because it's only needed for caret validation.
-    ///   And you can get it from [super::EditorEngine]. You can pass `0` if you don't have
+    ///   And you can get it from [crate::EditorEngine]. You can pass `0` if you don't have
     ///   it.
     pub vp: Dim,
 }
 
-// XMARK: Clever Rust, use of Drop to perform transaction close / end.
-
-impl Drop for EditorBufferMut<'_> {
-    /// Once [crate::validate_buffer_mut::EditorBufferMut] is used to modify the buffer,
-    /// it needs to run the validation checks to ensure that the buffer is in a valid
-    /// state. This is done using
-    /// [crate::validate_buffer_mut::perform_validation_checks_after_mutation].
-    ///
-    /// Due to the nature of `UTF-8` and its variable width characters, where the memory
-    /// size is not the same as display size. Eg: `a` is 1 byte and 1 display width
-    /// (unicode segment width display). `😄` is 3 bytes but it's display width is 2! To
-    /// ensure that caret position and scroll offset positions are not in the middle of a
-    /// unicode segment character, we need to run the validation checks.
-    fn drop(&mut self) { perform_validation_checks_after_mutation(self); }
+mod editor_buffer_mut_impl_block {
+    use super::*;
+
+    impl EditorBufferMut<'_> {
+        /// Returns the display width of the line at the caret (at it's scroll adjusted
+        /// row index).
+        pub fn get_line_display_width_at_caret_scr_adj_row_index(&self) -> ColWidth {
+            EditorBuffer::impl_get_line_display_width_at_caret_scr_adj(
+                *self.caret_raw,
+                *self.scr_ofs,
+                self.lines,
+            )
+        }
+
+        pub fn new<'a>(
+            lines: &'a mut VecEditorContentLines,
+            caret_raw: &'a mut CaretRaw,
+            scr_ofs: &'a mut ScrOfs,
+            sel_list: &'a mut SelectionList,
+            vp: Dim,
+        ) -> EditorBufferMut<'a> {
+            EditorBufferMut {
+                lines,
+                caret_raw,
+                scr_ofs,
+                sel_list,
+                vp,
+            }
+        }
+    }
+}
+
+pub struct EditorBufferMutNoDrop<'a> {
+    pub inner: EditorBufferMut<'a>,
+}
+
+mod editor_buffer_mut_no_drop_impl_block {
+    use super::*;
+
+    impl EditorBufferMutNoDrop<'_> {
+        pub fn new<'a>(
+            lines: &'a mut VecEditorContentLines,
+            caret_raw: &'a mut CaretRaw,
+            scr_ofs: &'a mut ScrOfs,
+            sel_list: &'a mut SelectionList,
+            vp: Dim,
+        ) -> EditorBufferMutNoDrop<'a> {
+            EditorBufferMutNoDrop {
+                inner: EditorBufferMut::new(lines, caret_raw, scr_ofs, sel_list, vp),
+            }
+        }
+    }
+}
+
+// XMARK: Clever Rust, use of Drop to perform transaction close / end. And also of "newtype" idiom / pattern.
+
+/// See the [Drop] implementation of `EditorBufferMut` which runs
+/// [crate::validate_buffer_mut::perform_validation_checks_after_mutation].
+///
+/// Due to the nature of `UTF-8` and its variable width characters, where the memory size
+/// is not the same as display size. Eg: `a` is 1 byte and 1 display width (unicode
+/// segment width display). `😄` is 3 bytes but it's display width is 2! To ensure that
+/// caret position and scroll offset positions are not in the middle of a unicode segment
+/// character, we need to run the validation checks.
+pub struct EditorBufferMutWithDrop<'a> {
+    pub inner: EditorBufferMut<'a>,
+}
+
+mod editor_buffer_mut_with_drop_impl_block {
+    use super::*;
+
+    impl EditorBufferMutWithDrop<'_> {
+        pub fn new<'a>(
+            lines: &'a mut VecEditorContentLines,
+            caret_raw: &'a mut CaretRaw,
+            scr_ofs: &'a mut ScrOfs,
+            sel_list: &'a mut SelectionList,
+            vp: Dim,
+        ) -> EditorBufferMutWithDrop<'a> {
+            EditorBufferMutWithDrop {
+                inner: EditorBufferMut::new(lines, caret_raw, scr_ofs, sel_list, vp),
+            }
+        }
+    }
+
+    impl Drop for EditorBufferMutWithDrop<'_> {
+        /// Once [crate::validate_buffer_mut::EditorBufferMut] is used to modify the buffer,
+        /// it needs to run the validation checks to ensure that the buffer is in a valid
+        /// state. This is done using
+        /// [crate::validate_buffer_mut::perform_validation_checks_after_mutation].
+        ///
+        /// Due to the nature of `UTF-8` and its variable width characters, where the memory
+        /// size is not the same as display size. Eg: `a` is 1 byte and 1 display width
+        /// (unicode segment width display). `😄` is 3 bytes but it's display width is 2! To
+        /// ensure that caret position and scroll offset positions are not in the middle of a
+        /// unicode segment character, we need to run the validation checks.
+        fn drop(&mut self) { perform_validation_checks_after_mutation(self); }
+    }
 }
 
 /// In addition to mutating the buffer, this function runs the following validations on the
@@ -70,7 +159,7 @@ impl Drop for EditorBufferMut<'_> {
 /// The drop implementation is split out into this separate function since that is how it
 /// used to be written in earlier versions of the codebase, it used to be called
 /// `apply_change()`. Also this function can be directly linked to in documentation.
-pub fn perform_validation_checks_after_mutation(arg: &mut EditorBufferMut<'_>) {
+pub fn perform_validation_checks_after_mutation(arg: &mut EditorBufferMutWithDrop<'_>) {
     // Check caret validity.
     adjust_caret_col_if_not_in_middle_of_grapheme_cluster(arg);
     adjust_caret_col_if_not_in_bounds_of_line(arg);
@@ -80,18 +169,6 @@ pub fn perform_validation_checks_after_mutation(arg: &mut EditorBufferMut<'_>) {
     }
 }
 
-impl EditorBufferMut<'_> {
-    /// Returns the display width of the line at the caret (at it's scroll adjusted
-    /// row index).
-    pub fn get_line_display_width_at_caret_scr_adj_row_index(&self) -> ColWidth {
-        EditorBuffer::impl_get_line_display_width_at_caret_scr_adj(
-            *self.caret_raw,
-            *self.scr_ofs,
-            self.lines,
-        )
-    }
-}
-
 /// ```text
 ///     0   4    9    1    2    2
 ///                   4    0    5
@@ -104,31 +181,34 @@ impl EditorBufferMut<'_> {
 ///   row
 /// ```
 fn adjust_caret_col_if_not_in_bounds_of_line(
-    editor_buffer_mut: &mut EditorBufferMut<'_>,
+    editor_buffer_mut: &mut EditorBufferMutWithDrop<'_>,
 ) {
     // Check right side of line. Clip scroll adjusted caret to max line width.
     let row_width = {
-        let line_display_width_at_caret_row =
-            editor_buffer_mut.get_line_display_width_at_caret_scr_adj_row_index();
-        let scr_ofs_col_index = editor_buffer_mut.scr_ofs.col_index;
+        let line_display_width_at_caret_row = editor_buffer_mut
+            .inner
+            .get_line_display_width_at_caret_scr_adj_row_index();
+        let scr_ofs_col_index = editor_buffer_mut.inner.scr_ofs.col_index;
         width(*line_display_width_at_caret_row - *scr_ofs_col_index)
     };
 
     // Make sure that the col_index is within the bounds of the given line width.
     let new_caret_col_index = col(std::cmp::min(
-        *editor_buffer_mut.caret_raw.col_index,
+        *editor_buffer_mut.inner.caret_raw.col_index,
         *row_width,
     ));
 
-    editor_buffer_mut.caret_raw.col_index = new_caret_col_index;
+    editor_buffer_mut.inner.caret_raw.col_index = new_caret_col_index;
 }
 
 pub fn is_scroll_offset_in_middle_of_grapheme_cluster(
-    editor_buffer_mut: &mut EditorBufferMut<'_>,
+    editor_buffer_mut: &mut EditorBufferMutWithDrop<'_>,
 ) -> Option<ColWidth> {
-    let scroll_adjusted_caret = *editor_buffer_mut.caret_raw + *editor_buffer_mut.scr_ofs;
+    let scroll_adjusted_caret =
+        *editor_buffer_mut.inner.caret_raw + *editor_buffer_mut.inner.scr_ofs;
 
     let line_at_caret = editor_buffer_mut
+        .inner
         .lines
         .get(usize(*scroll_adjusted_caret.row_index))?;
 
@@ -143,7 +223,7 @@ pub fn is_scroll_offset_in_middle_of_grapheme_cluster(
 
     if let Some(segment) = line_at_caret
         .is_display_col_index_in_middle_of_grapheme_cluster(
-            editor_buffer_mut.scr_ofs.col_index,
+            editor_buffer_mut.inner.scr_ofs.col_index,
         )
     {
         let diff = segment.unicode_width - display_width_of_str_at_caret;
@@ -154,32 +234,33 @@ pub fn is_scroll_offset_in_middle_of_grapheme_cluster(
 }
 
 pub fn adjust_scroll_offset_because_in_middle_of_grapheme_cluster(
-    editor_buffer_mut: &mut EditorBufferMut<'_>,
+    editor_buffer_mut: &mut EditorBufferMutWithDrop<'_>,
     diff: ColWidth,
 ) -> Option<()> {
-    editor_buffer_mut.scr_ofs.col_index += diff;
-    editor_buffer_mut.caret_raw.col_index -= diff;
+    editor_buffer_mut.inner.scr_ofs.col_index += diff;
+    editor_buffer_mut.inner.caret_raw.col_index -= diff;
     None
 }
 
 /// This function is visible inside the editor_ops.rs module only. It is not meant to
 /// be called directly, but instead is called by the [Drop] impl of [EditorBufferMut].
 pub fn adjust_caret_col_if_not_in_middle_of_grapheme_cluster(
-    editor_buffer_mut: &mut EditorBufferMut<'_>,
+    editor_buffer_mut: &mut EditorBufferMutWithDrop<'_>,
 ) -> Option<()> {
-    let caret_scr_adj = *editor_buffer_mut.caret_raw + *editor_buffer_mut.scr_ofs;
+    let caret_scr_adj =
+        *editor_buffer_mut.inner.caret_raw + *editor_buffer_mut.inner.scr_ofs;
     let row_index = caret_scr_adj.row_index;
     let col_index = caret_scr_adj.col_index;
-    let line = editor_buffer_mut.lines.get(row_index.as_usize())?;
+    let line = editor_buffer_mut.inner.lines.get(row_index.as_usize())?;
 
     // Caret is in the middle of a grapheme cluster, so jump it.
     let seg = line.is_display_col_index_in_middle_of_grapheme_cluster(col_index)?;
 
     scroll_editor_content::set_caret_col_to(
         seg.start_display_col_index + seg.unicode_width,
-        editor_buffer_mut.caret_raw,
-        editor_buffer_mut.scr_ofs,
-        editor_buffer_mut.vp.col_width,
+        editor_buffer_mut.inner.caret_raw,
+        editor_buffer_mut.inner.scr_ofs,
+        editor_buffer_mut.inner.vp.col_width,
         line.display_width,
     );
 
diff --git a/tui/src/tui/editor/editor_engine/validate_scroll_on_resize.rs b/tui/src/tui/editor/editor_engine/validate_scroll_on_resize.rs
index b619452a..bcd2847a 100644
--- a/tui/src/tui/editor/editor_engine/validate_scroll_on_resize.rs
+++ b/tui/src/tui/editor/editor_engine/validate_scroll_on_resize.rs
@@ -67,7 +67,7 @@ fn validate_vertical_scroll(args: EditorArgsMut<'_>) {
         if caret_scr_adj_row_index.check_overflows(max_row) == BoundsStatus::Overflowed {
             let diff = max_row - buffer.get_caret_scr_adj().row_index;
             let buffer_mut = buffer.get_mut_no_drop(vp);
-            buffer_mut.caret_raw.row_index -= diff;
+            buffer_mut.inner.caret_raw.row_index -= diff;
         }
     }
 
@@ -77,7 +77,7 @@ fn validate_vertical_scroll(args: EditorArgsMut<'_>) {
         if scr_ofs_row_index.check_overflows(max_row) == BoundsStatus::Overflowed {
             let diff = max_row - scr_ofs_row_index;
             let buffer_mut = buffer.get_mut_no_drop(vp);
-            buffer_mut.scr_ofs.row_index -= diff;
+            buffer_mut.inner.scr_ofs.row_index -= diff;
         }
     }
 
@@ -111,16 +111,16 @@ fn validate_vertical_scroll(args: EditorArgsMut<'_>) {
                 // Caret is above viewport.
                 let row_diff = scr_ofs_row_index - caret_scr_adj_row_index;
                 let buffer_mut = buffer.get_mut_no_drop(vp);
-                buffer_mut.scr_ofs.row_index -= row_diff;
-                buffer_mut.caret_raw.row_index += row_diff;
+                buffer_mut.inner.scr_ofs.row_index -= row_diff;
+                buffer_mut.inner.caret_raw.row_index += row_diff;
             }
             CaretLocRelativeToVp::Below => {
                 // Caret is below viewport.
                 let row_diff =
                     caret_scr_adj_row_index - (scr_ofs_row_index + vp.row_height);
                 let buffer_mut = buffer.get_mut_no_drop(vp);
-                buffer_mut.scr_ofs.row_index += row_diff;
-                buffer_mut.caret_raw.row_index -= row_diff;
+                buffer_mut.inner.scr_ofs.row_index += row_diff;
+                buffer_mut.inner.caret_raw.row_index -= row_diff;
             }
         }
     }
@@ -181,15 +181,15 @@ fn validate_horizontal_scroll(args: EditorArgsMut<'_>) {
         (CaretColWithinVp::No, CaretAtSideOfVp::Left) => {
             // Caret is to the left of viewport.
             let buffer_mut = buffer.get_mut_no_drop(engine.viewport());
-            *buffer_mut.scr_ofs.col_index = *caret_scr_adj_col_index;
-            *buffer_mut.caret_raw.col_index = ch(0);
+            *buffer_mut.inner.scr_ofs.col_index = *caret_scr_adj_col_index;
+            *buffer_mut.inner.caret_raw.col_index = ch(0);
         }
         (CaretColWithinVp::No, CaretAtSideOfVp::Right) => {
             // Caret is to the right of viewport.
             let buffer_mut = buffer.get_mut_no_drop(engine.viewport());
-            *buffer_mut.scr_ofs.col_index =
+            *buffer_mut.inner.scr_ofs.col_index =
                 *caret_scr_adj_col_index - *viewport_width + ch(1);
-            *buffer_mut.caret_raw.col_index = *viewport_width - ch(1);
+            *buffer_mut.inner.caret_raw.col_index = *viewport_width - ch(1);
         }
     }
 }
@@ -207,7 +207,7 @@ mod tests {
                 DEFAULT_SYN_HI_FILE_EXT};
 
     // REVIEW: [ ] add test for above viewport
-    
+
     // REVIEW: [ ] add test for below viewport
 
     // REVIEW: [x] add test for within viewport
@@ -226,8 +226,8 @@ mod tests {
 
         {
             let buffer_mut = buffer.get_mut_no_drop(viewport);
-            *buffer_mut.caret_raw = caret_raw(row(5) + col(0));
-            *buffer_mut.scr_ofs = scr_ofs(row(0) + col(0));
+            *buffer_mut.inner.caret_raw = caret_raw(row(5) + col(0));
+            *buffer_mut.inner.scr_ofs = scr_ofs(row(0) + col(0));
         }
 
         let editor_args_mut = EditorArgsMut {